The present disclosure relates generally to gas turbine engine architectures. More particularly, the present disclosure relates to systems for starting gas turbine engines.
Conventional dual spool gas turbine engines comprise a high pressure compressor and a high pressure turbine that define a core spool. The core spool generates a gas flow that drives a low pressure spool. The low pressure spool comprises a propulsor turbine, which powers a low pressure compressor and a fan. In such a configuration, operation of the engine is initiated by a starter that is coupled to the core spool through a tower shaft. The starter provides rotation to the core spool while fuel is injected into a combustor and ignited to initiate a combustion process that subsequently sustains rotation of the core spool and simultaneously the low pressure spool. Once the engine is rotating via the combustion process, the starter acts as a generator. The tower shaft requires coupling to a core spool shaft and the starter through elaborate gear systems. Furthermore, the tower shaft requires access to an axial length of the core spool shaft, which necessitates elongation of the core spool. There is, therefore, a need for a simpler starter-generator system that utilizes less space in the gas turbine engine.